About the Authors
Stanford Prevention Research Center, Stanford University School of Medicine, Stanford, California, United States of America
Division of General Medicine, Brigham and Women's Hospital and Department of Health Care Policy, Harvard Medical School, Boston, Massachusetts, United States of America
The authors have declared that no competing interests exist.
JM, NLS, and RSS designed the study. JM, NLS, and RSS analyzed the data. JM, JZA, NLS, and RSS contributed to writing the paper.